pub fn dp_rec_mc(amount: u32) -> u32 {
    match amount {
        0 => 0,
        1 => 1,
        2 => 1,
        3..5 => 2,
        5 => 1,
        6..10 => 1 + dp_rec_mc(amount - 5),
        10 => 1,
        11..20 => 1 + dp_rec_mc(amount - 10),
        20 => 1,
        20..30 => 1 + dp_rec_mc(amount - 20),
        30 => 1,
        30..50 => 1 + dp_rec_mc(amount - 30),
        50..100 => 1 + dp_rec_mc(amount - 50),
        100.. => amount / 100 + dp_rec_mc(amount % 100)
    }
}
